Blading of axial turbines



April 28, 1925.

FVLUSEL BLADING 0F AXIAL wumsmss Fild'AP'ril 21, 924

Patented Aprr Z8, i

"res

rnnnz Loser, or Banner, o'znonosnovanra.

BLADING OF AXIAL TURBINES.

Application filed April 21, 1924. Serial No. 708,083.

To all whom it may concern:

Be it known that T, FRANZ Losnn, a citizen of Czechoslovakia, residlng at Brunn @zechoslovakia, have invented certain new,

and useful Improvements in the Blading of Axial Turbines, of which the following is a specification.

This invention relates to elastic fluid turbines, particularly of the axial flow type, and the blading and guiding means therein.

The main object of the invention is to provide means in turbines, particularly in the low pressure ends thereof for issuing and partly expanding elastic fliuid from rotor blade rows through uncovered parts of their periphery and through stationary parts having gradually increasing conical interiors opening into the next following guide blade rows for obtaining ahigh endexpansion and good guiding effects between rotor blades and guide blades in the last stages and to increase the efliciency and performance of the turbines.

The efficiency of a turbine depends to a great extent on the manner in which the driving medium or fluid passes from one ring or row of blades to the next following one and of the final expansion in the individual blade rings. More particularly at the low pressure end of the turbine the differences in the volumes of the driving fluid between the, successive blade rings or rows are very great and therefore, according to this invention, it is very simple and easy to combine good guiding of the driving fluid between successive blade rings with high expansion of the driving fluid.

My invention effects improved passage of the driving fluid from a rotor blade ring to the next following stator blade ring, while at the same time greatly reducing the lealc age losses. .lVith these objects in view my invention consists in that the part of the turbine casing wall adjacent to Etlll Sll1- rounding the head ring or shroud and the blade heads, particularly their uncovered parts, increases in diameter towards the next following stator blade ring. Preferably I make this part of the turbine casing wall conical in shape, the generatrix of the conical surface being inclined to its axis in certain cases preferably at the Mach angle the nature of which will be described hereinafter. The head rings may project beyond the front edge of the rotor blades and may serve at their front ends for packing purposes.

In the annexed drawings Figs. 1 and 2 illustrate by way of example two embodiments of myl invention in diagrammatic axial section.

In Fig. 1 Z" indicates arotor blade and (Z the head ring secured to the outer end or head of the rotor blade i by means of a rivet n. The stator or guide blades Z are secured tothe turbine casing g or stator carrier in any desired or preferred manner. The head ring covers or extends over only part of the axial width of the rotor blades as indicated at b and projects with part of its width beyondthe front edge of such blades as indicated at c. vThis projecting part of the head ring is separated from the adjacent portion of the turbine casing wall by a small gap or clearance s constituting a tightening joint between successive pairs of rings. The part 7 of the periphery at the outlet side of the rotor blades Z" is not covered by theheadring (Z, and 2' denotes the increase of the guide blade length. The portion of the turbine casing wall opposite the rotor blade head and extending to the next following ring of stator blades Z increases in diameter towards the latter and is preferably conical in shape, its generatrix being inclined to its axis at an angle a which is in certain cases preferably equivalent to the Mach angle. 011 photographs of projectiles there has been observed a compression wave going out from the top of the projectile, said compression wave coinciding with the sound wave going out from the same point, which has been given the name Mach-angle. The same phenomenon is observed in regard to the working streams of steam in steam turbines.

The embodiment of my invention shown in Fig. 2 differs from that shown in Fig. 1 only in that the part c of the head ring d projecting beyond the front edge of the rotor blades Z is reinforced at its front end for instance by an inwardly projecting circumferential flange 0.

The invention is designed mainly for the low pressure element of a turbine and permits a smooth radial flow of the driving medium free from eddies from a rotor ring to the next following stator ring whereby a high final expansion is obtained and at the same time the leakage losses between successive pairs of rin 's are greatly reduced.

lVh-at I claim is:

1. In an axial fluid pressure turbine in combination with a casing and alternating rotor and stator elements, headrings secured to the free ends of the rotor blades and extending over only part of the axial width of the same, said headri gs forming on the entrance side of the rotor blades with the stationary part clearance or tightening spaces, the interior of the stationary part of the casing; being extended with gradually increasine diameter from substantially the rear end of said clearances of the rotor blades towards the front end of the next following, ring of stator blades so that the elas tic fluid is issued from the rotor blades partly through the uncovered part of their periphery and through said gradually increasing, interior of the stationary part into the next following guide blades.

2. In an axial fluid pressure turbine in combination with a casingrand alternating rotor and stator elements, head rings secured to the free ends of the rotor blades and extending orer only part of the axial width of the same, said headrings forming; on the entrance side of the rotor blades with the stationary part clearances for tightening purposes, the casing part being); extended and having an interior conical shape with increasing diameter from substantially the rear end of said clearances of the rotor blades towards the frontend of the next followingring of stator blades, the generatrix of the cone being included toits axis at the ll lach-angle.

3. In an axial fluid pressure turbine in combination with a casing and alternating rotor and stator elements, headrings secured to the free ends of the rotor blades and ex tending; from the entrance or front side of the rotor blades over part only of their axial width and propcctin beyond the entrance or front side of the rotor blade, said .headrings forming on the entrance side of the rotor blades with the stationary part tightening means or tightening clearances, the casing: being extended with gradually increasing; interior diameter from substantially the rear end of said tightening means of the rotor blades towards the front endof the next following ring of stator blades, the outer side of the front part of the head ring and the inner side of the nSillf" oppo site to said front end tightening means being coaxial with and separated from each other by the tightening; clearance.

el In an axial fluid pressure in combination with a casing and alternating rotor and stator elements, headrings secured to the free ends of the rotor blades and extending from the entrance or front side of the rotor blades over part only of their axial width and projecting beyond the entrance or front side of the rotor blade, said headrings forn'a ing with the stationary part tightening means on the entrance side of the rotor blades, the interior of the stationary part of the casing being extended in conical shape with gradually increasing diameter from substantially the rear end of said tightening means of the rotor blades towards the front end of the next following ring of stator blades.

5. In an elastic fluid turbine of the axial flow type, the combination with a stationary part or *asing and alternating rotor blades and stator or guide blades, of headrings secured to the peripheries of of rotor blades and extending over only part of the axial width of the same, said headrin srs providing with the stationary part tightening! means at the entra ce side of the rotor blades, the interior of the stationary part being extended in conical shape with gradually increasing diameter from substantialtr the rear end of said tightening means for the rotor blades towards the front side of the next following ring of guide blades.

(3. In an elastic fluid turbine of the axial flow type, the combination with a stationary part or casing and alternating rotor blades and guide blades, of a heath-inn secured to the periphery of a ring of rotor blades and extendingover only partof theaxial width of the same, the interior of the stationary part beingextended in conical shape with gradually increasing; dian'ieter from the periphery .of the ring of rotor blades towards the entrance or front end of the next follow inp; ringotguide blades,.so that the elastic fluid isis sued from the rotor blade ring partly through tllQJiOlPQOVQItBCl axial part of the periphery and through said gradually increasing conical interior of the stationary part into thenext following guide blade ring.

7. lin an elastic fluid turbine of the axial flow type, the combination with a ring of rotor blades,v of 1110211131 01 controlling the discharge of the fluid from said rotor blades comprising acasing or stationary part having its interior so shaped as, to l a substantially close to the .ends of the rotor blades at their entrance sides and partly across the ringgand then to spread mitwardly to permit the fluid to issue from anuncoyered part of the periphery of the ring of rotor blades as well as from their discharge sides. and a ring of guide bladessuitably disposed in said casing for receiving the fluid discharged from said rotor blades.

In testin'iony whereof Iallix my signature in presence of two witnesses.

FRANZ LOSER lYitnesses:

CARL Duorrsnn,

AN Ormtanf lll) Certificate of fiorrection.

It is hereby certified that in Letters Patent No. 1,535,612, granted April 28, 1925, upon the application of Franz Losel, of Brunn, Czechoslovakia, for an improve n ient in Bladjing of AXi a1 Turbines, an error appears in the printed specification requiring correction as follows: Page 2, line 61, claim 4, after the Word pressure insert the Word turbine; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Signed and sealed this 7th day of July, A. D. 1925.

SEAL WM. A. KINNAN,

Acting Omnvm'ssz'oner of Patents. 

